Preparation And Research Of Zinc Oxide Composite Functional Ceramics

ZnO linear resistance since the eighties of last century since research and development,has now become a new type of linear resistor components materials.The material has a smaller volume,high temperature conditions are not easy to be oxidized,the use of high temperature and light weight and other advantages.At present,ZnO-MgAl₂O₄-La₂O₃ and ZnO-ZnAl₂O₄-TiO₂ have been studied on the basis of the study of ZnO linear resistance doping on the domestic and foreign research on the doping of ZnO linear resistors.A three-element series of linear resistance of the doping characteristics of the in-depth study.Firstly,the effects of different oxides La₂O₃ and TiO₂ on the microstructure and electrical properties of ZnO linear ceramics were studied.The content of additives and the sintering preparation were studied.The fifth chapter focused on the effects of MgAl₂O₄ and ZnAl₂O₄ The spinel process and the ZnO linear resistance microstructure and electrical properties of the ZnO were investigated,and the ZnO linear resistance with excellent electrical properties was prepared.First,for the sintering system of ZnO-MgAl₂O₄-La₂O₃,when the content of La₂O₃ is more than 0.5 mol%,the microstructure and the electrical properties are excellent,the nonlinear coefficient reaches the minimum of 1.13,and the resistivity stability is also the best.The optimal sintering process of the ternary system is 1340oC×3h,the cooling rate is controlled at about 120oC/h.Calcination times are generally controlled at about 1-2 times,and the calcination temperature is typically 1150oC.Secondly,in the aspect of Zn O-ZnAl₂O₄-TiO₂ ternary sintering system,when the content of TiO₂ was increased to 6 mol%,the microstructure and electrical properties were optimized,and the resistivity and energy density reached the maximum in the composition of 6 mol%TiO₂ Value,the sintering powder at this time the nonlinear coefficient and the resistance temperature coefficient of variation to a minimum.The calcination temperature of TiO₂particles is controlled within 1000-1100oC,and the cooling rate is controlled at about 100oC/h.Finally,in the ZnO-MgAl₂O₄-La₂O₃ sintering system,the optimum sintering temperature should be controlled near 1340oC,the best content of MgAl₂O₄ spinel is 7.0 mol%,and the linearity of the linear resistance of the sintered powder is the smallest The In the ZnO-ZnAl₂O₄-TiO₂ ternary sintering system,when the content of ZnAl₂O₄ is 9 mol%,the nonlinear coefficient is1.17,the energy density is 512 J/cm³,the resistance temperature coefficient is-5.01×10^-3/oC,At this point the stability of the resistivity is relatively high,reaching 45.6?·cm.